The invention relates to a novel group of 3-tetrahydropyridin4-yl indole derivatives of the formula (I): 
wherein:
R1 is halogen, CF3, alkyl (1-3C), alkoxy (1-3C), CN or SCH3 
m the value 0, 1 or 2
R2 is H or alkyl (1-3C)
n has the value 3, 4, 5 or 6
R3 is halogen, alkyl (1-4C) or alkoxy (1-4C)
p has the value 0, 1, or 2 and salts thereof.
It has been found that the compounds having formula (I) show high affinity for the dopamine D2-receptor and are good serotonin reuptake inhibitors (SRI""s).
Preferred compounds of the invention are compounds having formula (I) wherein R1 hydrogen (i.e. m=0) or F, Cl, CH3 or CN, and m=1, R2 is H or CH3, n=4, R3 is hydrogen (i.e. p=0), or F or alkyl (1-4C), p=1, and the salts thereof. Especially preferred is the compound having formula (I) wherein (R1)m is F, R2 is hydrogen, n=4 and p=0, and the salts thereof.
It has been found that the compounds according to the invention show high affinity for both the dopamine D2 receptor and the serotonin reuptake site. This combination is useful for the treatment of schizophrenia and other psychotic disorders and might, allow for a more complete treatment of all disease symptoms (e.g. positive symptoms and negative symptoms).
The compounds show activity as antagonists at dopamine D2 receptors as they potentially antagonize apomorphine-induced climbing behavior mice. The compounds also show activity as inhibitors of serotonin reuptake, as they potentiate 5-HTP induced behaviour in mice.
The compounds are active in therapeutic models sensitive to clinically relevant antipsychotics (e.g. the conditioned avoidance response; Van der Heyden and Bradford, Behav. Brain Res., 1988, 31:61-67) and antidepressants or anxiolytics (e.g. suppression of stressinduced vocalization; van der Poel et al., Psychopharmacolgy, 1989, 97:147-148).
In contrast to clinically relevant dopamine D2 receptor antagonists the described compounds have a low propensity to induce catalepsy in rodents and as such are likely to induce less extrapyramidal side effects than existing antipsychotics agents.
The inhibitory activity of serotonin reuptake inherent in these compounds may be responsible for the therapeutic effects observed in behavioural models sensitive to either antidepressants or anxiolytics.
The compounds can be used for the treatment of affections or diseases of the central nervous system caused by disturbances in either the dopaminergic or serotonergic systems, for example: aggression, anxiety disorders, autism, vertigo, depression, disturbances of cognition or memory and in particular schizophrenia and other psychotic disorders.
Pharmacologically acceptable acids with which the compounds of the invention can form suitable acid addition salts are for example hydrochloric acid, sulphuric acid, phosphoric acid, nitric acid, and organic acids such as citric acid, fumaric acid, maleic acid, tartaric acid, acetic acid, benzoic acid, p-toluene sulphonic acid, methanesulphonic acid and naphthalene sulphonic acid.
The compounds are their acid addition salts can be brought into forms suitable for administration by means of suitable processes using auxiliary substances such as liquid and solid carrier materials.
The compounds having formula (I) can be obtained as follows: by reaction of a compound of formula (II) 
with a compound of the formula (III) 
wherein the symbols have the above meanings and L is a so-called leaving group, for example bromo.
This reaction is carried out in a solvent such as acetonitrile in the presence of triethylamine or K2CO3 and Kl at reflux temperature, or
a) by (i) reduction of the cyano group in a compound of formula (IV) 
xe2x80x83wherein A represents the group xe2x80x94(CH2)nxe2x88x921xe2x80x94CN, to the corresponding group xe2x80x94(CH2)nxe2x80x94NH2; and
(ii) reacting the obtained amine with an optionally substituted phthalic anhydride of the formula (V) 
xe2x80x83in which formula the symbols have the meanings give above.
Reaction step b (i) can be carried out for example with LiAlH4 in an organic solvent such as tetrahydrofuran at reflux temperature.
Reaction step (ii) can be carried out for example in organic solvents such as tetrahydrofuran and toluene at reflux temperature.
The starting compounds as used in method a) of the formula (II) can be obtained in a manner known per se by reaching an optionally substituted indole derivate with 4-piperidone.
The starting compounds used in method b) having formula (IV) can be obtained by reaction of a compound having formula (II) with a bromoalkyl nitrite of the formula Brxe2x80x94(CH2)nxe2x88x921xe2x80x94CN in a manner known per se.
The preparation of the compounds having formula (I) will now be described in more detail in the following Examples.